Does your babies sleep through the night?

Hannah
My LO turned 5 months on 6th. 
He had slept through the night since he was about 3 months. But about 3 weeks ago, he started waking up every 4 hours for milk. First I thought it would be temporary. A growth spert. But it has been going on every night for 3 weeks, and now, I feel like his sleeping habits went backwards. Has this happen w any of your LOs?